The invention relates to a method for monitoring a conveying system, i.e., for example, an elevator system, an escalator, a moving walkway, or the like, wherein, in the interest of improving the readability of the following description, the term “conveying system” is used hereinafter as a generic term for an elevator system, an escalator, or a moving walkway, and accordingly such specific conveying systems are to be understood as also being included at all times. The invention also relates to a device—also referred to hereinafter as a monitoring device—for monitoring and/or diagnosing such a conveying system according to the monitoring method, and a conveying system that is governed and configured in order to execute the method.
Methods and corresponding devices for monitoring elevator systems and the like are known per se. DE 10 2011 009 362 A discloses a method for monitoring an escalator. Therein, recorded operational sound data is compared with normal sound data. Thus, an operational sound is determined to be normal, for example, when the sound volume thereof lies in a range predetermined for the normal state, and regarded as abnormal when above or below this range.
WO 2014/200457 A discloses a method for monitoring an elevator system that is also based on capturing of sound data during operation of the elevator system. Therein, sound data is recorded at different instants, and a comparison should reveal changes. Recognized changes over time in the sound data are then used to output preventive maintenance instructions. Moreover, any fault situations should also be recognizable on the basis of the presence or absence of noise in the respective recorded sound data.
These approaches leave room for improvement insofar as, in the best case, an existing or imminent fault situation can be recognized thereby but without specific indications of a particular cause being given.
DE 10 2011 009 362 A, seemingly complementarily in that regard, proposes simultaneously collecting sound data with respect to a fixed part and movable part of the conveyor belt. Then, an indication of a fault cause should be given on the basis of a comparison of the sound data. This seems to require that the sound data be recorded when the movable part is moving past the fixed part, and that the sound data in this moment be sufficiently characteristic to recognize a fault. These conditions seem to allow only the detection of very specific fault situations.
US 2011/0240414 A1 proposes a system for monitoring an elevator, wherein signals of the elevator—e.g., a sound progression—are outputted in conjunction with operational data and a reference signal progression of the elevator. This data is made available to a service representative or an expert for diagnosis upon discovery of a relevant deviation.
US 2010/0094798 A1 likewise proposes a monitoring method for monitoring an escalator, wherein, in the presence of relevant sound differences from a reference sound progression, a frequency analysis is performed and a cause, such as a contamination or a stripping of parts, can be specified on the basis of the frequency analysis.
EP1050503 discloses a help system for elevators which involves checking to what extent an elevator follows an expected model progression or to what extent possible hypothetical faults occur.